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mm: handle THP in swap_*page_fs() 

Pages passed to swap_readpage()/swap_writepage() are not necessarily all
the same size - there may be transparent-huge-pages involves.

The BIO paths of swap_*page() handle this correctly, but the SWP_FS_OPS
path does not.

So we need to use thp_size() to find the size, not just assume PAGE_SIZE,
and we need to track the total length of the request, not just assume it
is "page * PAGE_SIZE".

Link: https://lkml.kernel.org/r/165119301488.15698.9457662928942765453.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
NeilBrown 2022-05-09 18:20:49 -07:00 committed by akpm
parent 2282679fb2
commit a1a0dfd56f
1 changed files with 13 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
mm/page_io.c
View File

@ -239,6 +239,7 @@ struct swap_iocb {
struct kiocb iocb;
struct bio_vec bvec[SWAP_CLUSTER_MAX];
int pages;
int len;
};
static mempool_t *sio_pool;
@ -261,7 +262,7 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
struct page *page = sio->bvec[0].bv_page;
int p;
if (ret != PAGE_SIZE * sio->pages) {
if (ret != sio->len) {
/*
* In the case of swap-over-nfs, this can be a
* temporary failure if the system has limited
@ -301,7 +302,7 @@ static int swap_writepage_fs(struct page *page, struct writeback_control *wbc)
sio = *wbc->swap_plug;
if (sio) {
if (sio->iocb.ki_filp != swap_file ||
sio->iocb.ki_pos + sio->pages * PAGE_SIZE != pos) {
sio->iocb.ki_pos + sio->len != pos) {
swap_write_unplug(sio);
sio = NULL;
}
@ -312,10 +313,12 @@ static int swap_writepage_fs(struct page *page, struct writeback_control *wbc)
sio->iocb.ki_complete = sio_write_complete;
sio->iocb.ki_pos = pos;
sio->pages = 0;
sio->len = 0;
}
sio->bvec[sio->pages].bv_page = page;
sio->bvec[sio->pages].bv_len = PAGE_SIZE;
sio->bvec[sio->pages].bv_len = thp_size(page);
sio->bvec[sio->pages].bv_offset = 0;
sio->len += thp_size(page);
sio->pages += 1;
if (sio->pages == ARRAY_SIZE(sio->bvec) || !wbc->swap_plug) {
swap_write_unplug(sio);
@ -371,8 +374,7 @@ void swap_write_unplug(struct swap_iocb *sio)
struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
int ret;
iov_iter_bvec(&from, WRITE, sio->bvec, sio->pages,
PAGE_SIZE * sio->pages);
iov_iter_bvec(&from, WRITE, sio->bvec, sio->pages, sio->len);
ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
if (ret != -EIOCBQUEUED)
sio_write_complete(&sio->iocb, ret);
@ -383,7 +385,7 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
int p;
if (ret == PAGE_SIZE * sio->pages) {
if (ret == sio->len) {
for (p = 0; p < sio->pages; p++) {
struct page *page = sio->bvec[p].bv_page;
@ -415,7 +417,7 @@ static void swap_readpage_fs(struct page *page,
sio = *plug;
if (sio) {
if (sio->iocb.ki_filp != sis->swap_file ||
sio->iocb.ki_pos + sio->pages * PAGE_SIZE != pos) {
sio->iocb.ki_pos + sio->len != pos) {
swap_read_unplug(sio);
sio = NULL;
}
@ -426,10 +428,12 @@ static void swap_readpage_fs(struct page *page,
sio->iocb.ki_pos = pos;
sio->iocb.ki_complete = sio_read_complete;
sio->pages = 0;
sio->len = 0;
}
sio->bvec[sio->pages].bv_page = page;
sio->bvec[sio->pages].bv_len = PAGE_SIZE;
sio->bvec[sio->pages].bv_len = thp_size(page);
sio->bvec[sio->pages].bv_offset = 0;
sio->len += thp_size(page);
sio->pages += 1;
if (sio->pages == ARRAY_SIZE(sio->bvec) || !plug) {
swap_read_unplug(sio);
@ -521,8 +525,7 @@ void __swap_read_unplug(struct swap_iocb *sio)
struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
int ret;
iov_iter_bvec(&from, READ, sio->bvec, sio->pages,
PAGE_SIZE * sio->pages);
iov_iter_bvec(&from, READ, sio->bvec, sio->pages, sio->len);
ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
if (ret != -EIOCBQUEUED)
sio_read_complete(&sio->iocb, ret);